1 files changed, 92 insertions, 0 deletions
diff --git a/strftime.js b/strftime.js
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+/* Port of strftime(). Compatibility notes:
+ *
+ * %c - formatted string is slightly different
+ * %D - not implemented (use "%m/%d/%y" or "%d/%m/%y")
+ * %e - space is not added
+ * %E - not implemented
+ * %h - not implemented (use "%b")
+ * %k - space is not added
+ * %n - not implemented (use "\n")
+ * %O - not implemented
+ * %r - not implemented (use "%I:%M:%S %p")
+ * %R - not implemented (use "%H:%M")
+ * %t - not implemented (use "\t")
+ * %T - not implemented (use "%H:%M:%S")
+ * %U - not implemented
+ * %W - not implemented
+ * %+ - not implemented
+ * %% - not implemented (use "%")
+ *
+ * strftime() reference:
+ * http://man7.org/linux/man-pages/man3/strftime.3.html
+ *
+ * Day of year (%j) code based on Joe Orost's answer:
+ * http://stackoverflow.com/questions/8619879/javascript-calculate-the-day-of-the-year-1-366
+ *
+ * Week number (%V) code based on Taco van den Broek's prototype:
+ * http://techblog.procurios.nl/k/news/view/33796/14863/calculate-iso-8601-week-and-year-in-javascript.html
+ */
+export default function strftime(sFormat, date) {
+    if (!(date instanceof Date)) date = new Date();
+    let nDay = date.getDay(),
+        nDate = date.getDate(),
+        nMonth = date.getMonth(),
+        nYear = date.getFullYear(),
+        nHour = date.getHours(),
+        aDays = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'],
+        aMonths = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
+        aDayCount = [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334],
+        isLeapYear = function () {
+            return (nYear % 4 === 0 && nYear % 100 !== 0) || nYear % 400 === 0;
+        },
+        getThursday = function () {
+            let target = new Date(date);
+            target.setDate(nDate - ((nDay + 6) % 7) + 3);
+            return target;
+        },
+        zeroPad = function (nNum, nPad) {
+            return ('' + (Math.pow(10, nPad) + nNum)).slice(1);
+        };
+    return sFormat.replace(/%[a-z]/gi, function (sMatch) {
+        return {
+            '%a': aDays[nDay].slice(0, 3),
+            '%A': aDays[nDay],
+            '%b': aMonths[nMonth].slice(0, 3),
+            '%B': aMonths[nMonth],
+            '%c': date.toUTCString(),
+            '%C': Math.floor(nYear / 100),
+            '%d': zeroPad(nDate, 2),
+            '%e': nDate,
+            '%F': date.toISOString().slice(0, 10),
+            '%G': getThursday().getFullYear(),
+            '%g': ('' + getThursday().getFullYear()).slice(2),
+            '%H': zeroPad(nHour, 2),
+            '%I': zeroPad((nHour + 11) % 12 + 1, 2),
+            '%j': zeroPad(aDayCount[nMonth] + nDate + ((nMonth > 1 && isLeapYear()) ? 1 : 0), 3),
+            '%k': '' + nHour,
+            '%l': (nHour + 11) % 12 + 1,
+            '%m': zeroPad(nMonth + 1, 2),
+            '%M': zeroPad(date.getMinutes(), 2),
+            '%p': (nHour < 12) ? 'AM' : 'PM',
+            '%P': (nHour < 12) ? 'am' : 'pm',
+            '%s': Math.round(date.getTime() / 1000),
+            '%S': zeroPad(date.getSeconds(), 2),
+            '%u': nDay || 7,
+            '%V': (function () {
+                let target = getThursday(),
+                    n1stThu = target.valueOf();
+                target.setMonth(0, 1);
+                let nJan1 = target.getDay();
+                if (nJan1 !== 4) target.setMonth(0, 1 + ((4 - nJan1) + 7) % 7);
+                return zeroPad(1 + Math.ceil((n1stThu - target) / 604800000), 2);
+            })(),
+            '%w': '' + nDay,
+            '%x': date.toLocaleDateString(),
+            '%X': date.toLocaleTimeString(),
+            '%y': ('' + nYear).slice(2),
+            '%Y': nYear,
+            '%z': date.toTimeString().replace(/.+GMT([+-]\d+).+/, '$1'),
+            '%Z': date.toTimeString().replace(/.+\((.+?)\)$/, '$1')
+        }[sMatch] || sMatch;
+    });
+}
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